AT TWENTY-THREE I WAS LIVING IN Los Angeles, if you can call it living. I had nothing else to do. A detective I knew named Sean Risling had me working on an encyclopedia of poisonous orchids he was putting together. I sampled and researched and wrote. At night I bought little twenty-dollar bindles of cocaine and sometimes cheaper bags of heroin wrapped in pages of Cat Fancy magazine on Sunset Boulevard. I slept in a series of hotel rooms in Hollywood. When Constance Darling, the famous detective from New Orleans, came to town on the HappyBurger Murder Case and needed an assistant, Sean introduced us. Risling said little and knew much.

Constance was famous — famous to other detectives, at least. Years ago, when we were finished being children, my friend Tracy found a copy of Jacques Silette’s little yellow book Détection in my parent’s musty, bitter house in Brooklyn. After that we were ruined: being detectives was all that mattered to us. Especially Tracy, who became the best detective of us all — and when she vanished a few years later became a mystery herself, leaving only a Tracy-shaped hole behind, a paper doll cut out from the page.

To me, Silette and his students were rock stars, celebrities. I was always surprised when no one else seemed to have heard of them.

Wasn’t solving mysteries important? Didn’t the truth matter? Of course, Silette had foreseen this. He knew the truth always was, and always would be, the most unpopular point of view. “If there is anything that can unify us,” he wrote to Constance during the Paris uprising, already old and bitter, “it is our love of deceit and lies, and our abhorrence of the truth.”

Constance was pleased enough with me when the HappyBurger case was done, but I hardly let myself hope she would take me on as a permanent assistant. Or as close to permanent as we get; she died three years later, shot in New Orleans for the few hundred bucks she had in her Chanel bag, a bag that was now mine.

Constance had set me up in a room at the Chateau Marmont down the hall from her own. I didn’t know what she was doing now that we were done with the case. I figured I’d hang around the Marmont until she kicked me out. I had no place to go, anyway. I’d let my cheap Hollywood Boulevard hotel room go when she hired me, and when we were done I’d sleep in the bus station or maybe in Griffin Park, up by the observatory. When Sean paid me I’d get another hotel room or a room in a share.

But the next morning Constance called me to her room.

“DeWitt,” she said. She was sitting at a table drinking a cup of coffee with chicory, a woody smell I didn’t recognize at the time but would later. She peered at me, head tilted like a little bird. Constance was already old. She was born old, with her Chanel suits and spectator pumps and white hair in a topknot.

“DeWitt, are you free for another job tomorrow?”

“Sure,” I said, heart thumping.

“Do you drive?” she asked.

“Legally?”

Constance flicked her hand in the air. The law was for people who needed instructions, she would later tell me. The same people who needed to be told not to put a baby in the dryer or a dog in the microwave.

“We’re going to Las Vegas,” she said. “Or close to it. Do you know the way?”

“I’ll get a map,” I said. “Give me the address and I’ll plan it tonight.”

She nodded and tossed me the keys to her car. For the trip she’d rented a Jaguar identical to the one she drove in New Orleans, as she would in every city we visited.

That night I plotted out our trip on a few maps. I asked the concierge at the hotel for recommended stops along the way, and I marked the least filthy gas stations and the best date shakes. When I was done I took the Jaguar and drove around Los Angeles, up Sunset Boulevard into the hills and out toward the ocean.

It had been eight years since Tracy had disappeared from a subway platform in New York City. We were going to grow up to be great detectives together, Tracy and Kelly and I. We were detectives already, just not great ones. But we were pretty good for kids.

Now Tracy was gone and Kelly was becoming someone ugly. She was so devastated by our inability to find Tracy that I was pretty sure she’d never left New York City at all, scared of overlooking a single clue, missing the phone call that would explain everything. She hated me for leaving. She hated me for being here while Tracy, so much wiser and kinder and prettier, was gone. I agreed. But there was nothing I could do about it.

On the end of the Sunset Strip I pulled over to a pay phone and put in a handful of change. First I called Tracy. She’d disappeared in 1987. No one knew if she was alive or dead. Kelly had fixed her old phone number so it was never given away, never changed. I called it. No one answered.

I’m here, I said aloud, or maybe thought. I’d spent so much time alone, I couldn’t tell the difference sometimes. I’m here, just where we were supposed to be.

But Tracy didn’t answer, because Tracy wasn’t there.

Next I called Kelly. She picked up the phone and didn’t say anything. I didn’t say anything either. I knew she knew it was me and I knew she knew exactly where I was and who I was working for, the great Constance Darling. How could she not know? Wouldn’t the angels be singing? Wouldn’t Silette’s hand come down from heaven and mark us, all over again, with the mark of Cain, the stain of the detective, the scar of initiation, as he had when we’d read his book? Wasn’t it the most obvious thing in the world that something had actually happened, that my course, finally, was changed?

Genius, we were learning, was only skin deep. Brilliance is as brilliance does. Our ability to solve mysteries was not particularly helpful in actual living.

We didn’t say anything. The silence on the phone sounded like Brooklyn. After a minute Kelly hung up and I had a sour taste in my mouth and I remembered that even the best things would never be good again.

I drove back to the hotel and used a sewing needle and the ink from a ballpoint pen to give myself a tattoo of a four-leaf clover on the top of my left foot, where it hurt the most. Maybe someday someone would ask me about it, and I would get to tell them about today. This day when everything changed. And then everything would change again, because someone cared enough to ask.

The next day we started late. Constance was always a night person and liked her morning routine of coffee and poached eggs and meditation. She was quiet on the drive and almost seemed anxious, the tiniest cracks showing in her cool veneer. I asked a few times if she wanted to stop and she didn’t, my carefully plotted breaks just spots on the map.

We didn’t go into the city proper but circled around it, starting at the cheaper suburbs and moving up to streets with mansions and gates.

“Here it is,” she said. “This is the house.”

A curved driveway led to a high fence surrounding a property lush with palms and hedges and desert flowers. Behind the plants I saw glimpses of a white mansion that looked like it’d been spun out of cardboard and cotton candy, brand new, and dropped in Las Vegas. I heard rustling in the plants — animals or maybe other humans were moving around, hiding.

“Wait here,” she said. “I may be a while.”

I waited outside the gate and watched Constance ring the buzzer, say a few words, and get buzzed in. She disappeared into the hedges. I waited. Even with the air full blast, the sun was hot and I felt a little queasy.

Nine minutes later I saw a man in blue jeans and a black shirt and cowboy boots pulling her away from the house.

I tried to catch Constance’s eye but she didn’t see me. Constance looked like she always did — too intelligent and a little bit bored.

But when she tried to take her arm back from the man in the black shirt, he twisted, hard, and didn’t let go.

I watched for another minute. They argued. Constance didn’t look scared. They exchanged a few more words and it didn’t look too heated, but when she tried to pull away again the man in the black shirt held on tight.

I got out of the car and left the motor running and the door open. No one saw me. I went up to the gate and pulled a cheap little Saturday night special from the back of my waistband and pointed it at the man’s heart.

Constance and the man were about fifteen feet away. I’d bought the gun when I’d first come to L.A. I liked to travel armed back then. It was the only way I knew to speed up time, to bend reality to my will. Constance taught me more effective and less painful ways to make thoughts real.

I knocked on the gate with the gun.

“Hey,” I said.

Constance and the man turned to look at me.

“Who are you?” the man said.

“Let her go,” I said.

He looked at me and didn’t let her go. Constance looked bored. She let out a big sigh, like it was all too stupid for words. Which of course it was. It always is.

“Get your fucking hands off her,” I said.

He looked at me and did not take his fucking hands off her.

“You think I’m kidding?” I cocked the gun.

“You’ll be three,” I said. “Three dead.”

He didn’t let go.

“It gets easier every time,” I said. It wasn’t true. “I think I’m starting to like it.”

Another man came from the direction of the house. Maybe he was young or maybe he was just one of those men whose face never grows up. He was thin and...